Concrete wall slabs in tilt-up construction are temporarily braced in a vertical position until they can be tied together with other construction units. A conventional bracing system comprising tilt-up braces, knee braces and lace braces is shown and described in detail in U.S. Pat. No. 4,011,638. The foot portions of the tilt-up braces of that and other conventional bracing systems are secured to a concrete floor slab by one form or another of expansion anchors. Anchors of that type adequately serve the purpose if they are properly and carefully installed. Such expansion anchors are frequently reduced in strength to a substantial degree for one reason or another, such as making the expansion anchor holes oversized, insufficient torqueing of the bolts, and so on. Such expansion anchors can also be loosened by wind buffeting or by bumping into a braced wall panel or slab when an adjoining panel is being set and braced.